Occupational exposure to particulate matter (PM) is a known risk factor for numerous adverse health effects including asthma, chronic obstructive pulmonary disease, bronchitis, and decreased lung function. Knowledge of the timing of exposure risks is critical for effective risk mitigation. However, the benefits of time-resolved exposure data must be weighed against the regulatory requirements for assessing compliance - namely the collection of a time-integrated filter sample. An ideal exposure measurement technology would provide real-time exposure data in conjunction with a time-integrated sample that satisfies requirements for regulatory compliance monitoring. The technology should be lightweight, compact, and low-cost. Current real-time aerosol equipment does not meet these needs. Therefore, to reduce workers? exposure to pollutants, improved methods of time- resolved particulate matter quantification are needed. The objective of the proposed work is to develop a low-cost method for assessing time-resolved aerosol exposure using differential pressure sensors. The proposed device will use filter pressure drop coupled with knowledge of time-integrated mass gain of that filter. Filter mass gain provides a sample-specific measure to calibration the data, allowing pressure drop to be used as an estimation of time-resolved aerosol concentration. I hypothesize that time-resolved measure of filter pressure drop can be used as a low-cost method of determining real-time aerosol concentrations while still complying with regulatory requirements for assessing worker exposure. This proposed work is relevant to multiple NORA sectors including Agriculture/Forestry, Construction, Manufacturing, and Mining. All four sectors have extensive workplace exposure to particulate matter. The proposed work will complement the NIOSH strategic goal of reducing the occurrence of occupational respiratory diseases Specific Aim 1: Develop a low-cost method for quantifying time-resolved aerosol concentrations based on filter pressure drop simultaneously with a time-integrated gravimetric measurement Specific Aim 2: Develop a semi-empirical model that relates changes in filter pressure drop to filter media characteristics, aerosol properties, and environmental conditions Specific Aim 3: Evaluate both the model and the concentration via pressure device through field experiments